Enhancement of hydrogen evolution at cobalt-zinc deposited graphite electrode in alkaline solution

Doner A., Solmaz R., KARDAŞ G.

INTERNATIONAL JOURNAL OF HYDROGEN ENERGY, vol.36, no.13, pp.7391-7397, 2011 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 36 Issue: 13
  • Publication Date: 2011
  • Doi Number: 10.1016/j.ijhydene.2011.03.083
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.7391-7397
  • Keywords: Cobalt-zinc coating, Platinum electrodeposition, Electrochemical deposition, Electrocatalysis, Hydrogen evolution reaction, ELECTROCATALYTIC PROPERTIES, ELECTROCHEMICAL DEPOSITION, NICU COATINGS, ALLOYS, KINETICS, CO, BEHAVIOR, CATHODE, SURFACE
  • Çukurova University Affiliated: Yes


Thin Co layers were electrochemically deposited on a graphite electrode at different deposition current densities and thicknesses. After determining the best deposition conditions for hydrogen evolution (deposition current density and thickness), co-deposits of Co with Zn were prepared on the graphite electrode. The binary coatings prepared on the graphite electrode (CoZn) were etched in a concentrated alkaline solution (30% NaOH) to produce a porous and electrocatalytic surface suitable for use in the hydrogen evolution reaction (HER). After the leaching process, a low amount of Pt was deposited onto the etched CoZn deposit in order to further improve the catalytic activity of the electrode for the HER. The HER activity is assessed by recording cathodic current potential curves, electrochemical impedance spectroscopy (EIS) and electrolysis techniques. Chemical composition of layers after alkaline leaching was determined by energy dispersive X-ray (EDX) analysis. The surface morphologies of coatings were investigated by scanning electron microscopy (SEM). It was found that, the HER activity of coatings depends on the metal ratio of Co and Zn, deposition current density and the thickness of coatings. The alkaline leached CoZn coating has a compact and porous structure as well as good electrocatalytic activity for the HER in alkaline media. Moreover, deposition of a low amount of Pt over the CoZn can further enhance its hydrogen evolution activity. Copyright (C) 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.